Computation of Wave Transmission Coefficients at Detached Breakwaters for Shoreline Response Modeling

Wave transmission is a leading parameter determining the response of the shoreline to a detached breakwater. Wave transmission properties can vary significantly depending on structure configuration and composition, and they can also vary over different time scales as controlled by tidal variations or changes in incident wave conditions. Therefore, the capability to predict shoreline response to detached breakwaters for a wide range of engineering conditions requires an expression for the wave transmission coefficient that is valid over a broad range of environmental forcing and breakwater designs. To improve the predictive capability of the GENESIS shoreline response numerical model, several published empirical formulas for the wave transmission coefficient were evaluated. A dominant mode approach introduced by Ahrens provided the most appropriate general predictive procedure suitable for shoreline response modeling. The application of an artificial neural network for predicting wave transmission was also evaluated and found to be a suitable general predictive procedure.